Evaluation of Ultrasonic Testing Parameters of Drill Key Die Soldered Joints

Drill key dies are elements of drilling equipment used to ensure reliable grip during installation and dismantling of drill pipes. High loads and aggressive operating conditions set quality control requirements of these elements. Timely diagnostics of fatigue damage and deformations at early stages, as well as the application of non-destructive methods, help minimize the risk of accidents and increase the service life of drilling equipment. The work is aimed at determining the optimal parameters of ultrasonic waves for assessing the acoustic anisotropy of drill key dies, taking into account the quality control of soldered joints. The article presents the results of studies on assessing acoustic anisotropy and searching for continuity defects in drill key dies, allowing determination of the optimal parameters of ultrasonic waves for quality control of die soldered joints. Acoustic anisotropy was assessed by means of two wavetypes: the head wave and the Rayleigh wave. The study included the analysis of various frequency ranges in order to identify maximum sensitivity to the anisotropic state of the samples. Ultrasonic testing of soldered joints quality was performed both without and with a standard sample, allowingthe estimation the of amplitude spread of signals reflected from the soldered joint. To improve testing accuracy, the immersion method was chosen eliminating the influence of surface contact on quality. Testing was performed on 12 samples, each of which was checked at 8-9 points using a DIO1000 PA ultrasonic flaw detector and a P112-10 transducer. The average value of the signal amplitude from the free boundary of the sample served as the reference value. During the experiments, the most sensitive frequency range of piezoelectric transducers for testing the anisotropy of drill lock dies was determined. It was found that the die bases have significant anisotropy, which decreases after soldering. The obtained data on the amplitude of the acoustic wave reflected from the copper film coincide with the calculated values, confirming the efficiency of the immersion method for testing the continuity of joints. It was found that in areas with soldering defects, the amplitude of the reflected signal increases significantly compared to defect-free areas, which provides prospects for increasing the reliability and durability of the drilling tool.